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| author | Heiko Carstens <hca@linux.ibm.com> | 2021-06-14 23:09:20 +0300 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-06-18 17:41:24 +0300 |
| commit | da9057576785aaab52e706e76c0475c85b77ec14 (patch) | |
| tree | d69c79fe3e4159e30bdc21ce11640154385cda5d | |
| parent | 1b2f281f45afd5def728288df9732a74e8d12582 (diff) | |
| download | linux-da9057576785aaab52e706e76c0475c85b77ec14.tar.xz | |
s390/mem_detect: fix tprot() program check new psw handling
The tprot() inline asm temporarily changes the program check new psw
to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.
This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.
To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
| -rw-r--r-- | arch/s390/boot/mem_detect.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c index 2c5a9c61b101..4e17adbde495 100644 --- a/arch/s390/boot/mem_detect.c +++ b/arch/s390/boot/mem_detect.c @@ -118,24 +118,30 @@ static int diag260(void) static int tprot(unsigned long addr) { - unsigned long pgm_addr; + unsigned long reg1, reg2; int rc = -EFAULT; - psw_t old = S390_lowcore.program_new_psw; + psw_t old; - S390_lowcore.program_new_psw.mask = __extract_psw(); asm volatile( - " larl %[pgm_addr],1f\n" - " stg %[pgm_addr],%[psw_pgm_addr]\n" + " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" + " epsw %[reg1],%[reg2]\n" + " st %[reg1],0(%[psw_pgm])\n" + " st %[reg2],4(%[psw_pgm])\n" + " larl %[reg1],1f\n" + " stg %[reg1],8(%[psw_pgm])\n" " tprot 0(%[addr]),0\n" " ipm %[rc]\n" " srl %[rc],28\n" - "1:\n" - : [pgm_addr] "=&d"(pgm_addr), - [psw_pgm_addr] "=Q"(S390_lowcore.program_new_psw.addr), - [rc] "+&d"(rc) - : [addr] "a"(addr) + "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" + : [reg1] "=&d" (reg1), + [reg2] "=&a" (reg2), + [rc] "+&d" (rc), + "=Q" (S390_lowcore.program_new_psw.addr), + "=Q" (old) + : [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw), + [addr] "a" (addr) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return rc; } |